主题：通过目录树返回项目中所有表名称及表中的所有列

其实很简单：

Dim trv As WinForm.TreeView = e.Form.Controls("TreeView1")
For Each dt As DataTable In DataTables
    Dim nd As WinForm.TreeNode = trv.Nodes.Add(dt.name)
    For Each dc As DataCol In dt.DataCols
        nd.Nodes.Add(dc.name)
    Next
Next